JP2009011595A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To positively prevent the occurrence of skipping stitches, breakage or hangnail of a needle thread loop by preventing the separation of a sewing needle and a hook. <P>SOLUTION: This sewing machine has a sewing needle 12 that forms a needle thread loop 13a by a sewing thread 13, a shuttle 3 having a hook 3c that catches the needle thread loop 13a by a rotation motion and a driver 5 that reciprocably rotates the shuttle 3 by a rotation motion. The driver 5 is provided with a needle-rear receiving part 5e that supports the back surface opposing the hook 3c of the sewing needle 12 and a needle-front receiving part 5f that supports the front surface of the sewing needle 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sewing machine provided with a driver for rotating an inner hook so as to be able to reciprocate.

  2. Description of the Related Art Conventionally, a sewing machine having a half-turn hook that performs sewing by capturing an upper thread loop of a sewing thread formed by a sewing needle with a sword tip of a rotating inner hook and crossing with a lower thread is used ( For example, see Patent Document 1).

  FIG. 6 is a schematic perspective view showing an example of a half rotary hook in a sewing machine equipped with a conventional half rotary hook. As shown in FIG. 6, the half rotary hook 15 in the conventional sewing machine 16 has a bobbin case (not shown). An inner hook 17 to be held, a driver 18 for rotating the inner hook 17 so as to be reciprocally movable, and a substantially hook-shaped cauldron 19 for holding the inner hook 17 so as to be rotatable inside are provided. The driver 18 is fixed to a shuttle shaft 20 that is driven in synchronism with a sewing machine main shaft (not shown), and reciprocally rotates following the rotation of the shuttle shaft 20. Are rotated by both ends in the rotational direction of the motor so as to be reciprocally movable by the rotation of the driver 18.

  As shown in FIG. 7, the inner hook 17 is inserted into the needle hole 22 a of the sewing needle 22 when the sewing needle 22 that moves up and down moves up after reaching the bottom dead center and positioned inside the inner hook 17. The upper thread loop 23 a formed on the rear side of the sewing needle 22 as viewed from the operator side of the sewing needle 22 by the sewing thread 23 is captured by the sword tip 17 a formed on the peripheral edge of the inner hook 17. Thereafter, the inner hook 17 is pressed by the driver 18 and rotated, so that the upper thread loop 23 a passes through the bobbin case housed in the inner hook 17. As a result, the sewing machine 16 performs sewing by crossing the lower thread supplied from the bobbin case to the needle drop position through the needle hole 22a of the needle plate into the upper thread loop 23a.

  In such a sewing machine 16, when the sewing needle 22 moves up after reaching the bottom dead center, if the position of the sewing needle 22 shifts to the rear side, the rear end of the sewing needle 22 is caused by the sword tip 17a of the inner hook 17. The upper thread loop 23a formed on the side cannot be reliably captured, and stitch skipping occurs, or the sword tip 17a pierces the upper thread loop 23a, thereby cutting the entire upper thread loop 23a. There is a possibility that a thread breakage or a scissors cutting a part of the upper thread loop 23a may occur. For this reason, a needle rear side receiving portion 18 a for supporting the rear surface of the sewing needle 22 when the sewing needle 22 is lowered and positioned inside the inner hook 17 is formed at one end portion of the driver 18. By restricting the movement of the sewing needle 22 to the rear side by the needle rear side receiving portion 18a, it is possible to prevent the occurrence of stitch skipping, thread breakage, or scalding.

JP 2002-52276 A

  However, in the conventional sewing machine 16 as described above, the front side of the sewing needle 22 when the sewing needle 22 is lowered and positioned inside the intermediate hook 17 is opened. For this reason, when there is a step in the fabric 25 to be sewn or depending on the direction of the fabric of the fabric 25, the sewing needle 22 may move to the front side which is the operator side of the sewing machine 16. In such a case, when the upper thread loop 23a formed by the sewing needle 22 is captured by the sword tip 17a of the inner hook 17, the sewing needle 22 and the sword tip 17a are separated from each other. Therefore, the upper thread loop 23a is separated by the sword tip 17a. May not be able to be caught, or the sword tip 17a may pierce the upper thread loop 23a, causing the upper thread loop 23a to break or bend. It was.

  The present invention has been made in view of these points. By preventing the sewing needle and the sword from being separated from each other, stitch skipping, thread breakage of the upper thread loop, or scrunching may occur. An object of the present invention is to provide a sewing machine that can reliably prevent the above.

  In order to achieve the above object, the sewing machine according to the first aspect of the present invention is characterized in that an inner hook provided with a sewing needle that forms an upper thread loop by a sewing thread and a sword tip that captures the upper thread loop by a rotating operation. And a driver for rotating the inner hook so as to be able to reciprocate by a rotating operation, the driver including a needle rear side receiving portion that supports one surface of the sewing needle facing the sword tip, and the sewing needle. And a needle front side receiving portion for supporting the other surface on the opposite side.

  According to the first aspect of the present invention, the front surface of the sewing needle is supported by the needle front side receiving portion from when the sewing needle is located at the bottom dead center until it exceeds the position where the sword tip captures the upper thread loop. Since the rear surface is supported by the needle rear side receiving portion, it is possible to regulate not only the backward movement of the sewing needle but also the forward movement, thereby making the formation position of the upper thread loop constant. it can.

  Further, the sewing machine according to the second aspect of the invention is characterized in that the needle front side receiving portion and the needle rear side receiving portion have a sharp gap between the two receiving portions and move up and down. The sewing needle is formed in a shape that gradually narrows as the sewing needle rises in accordance with the diameter dimension of the sewing needle when the sewing needle is positioned in the gap.

  According to the second aspect of the present invention, the size of the gap between the needle front side receiving portion and the needle rear side receiving portion is set so that the sewing needle is positioned in the gap between the needle front side receiving portion and the needle rear side receiving portion. The front and rear surfaces of the sewing needle are more reliably supported by the needle front side receiving portion and the needle rear side receiving portion by forming the taper so that it gradually becomes narrower as the sewing needle rises. be able to. Thereby, the movement of the sewing needle in the front-rear direction can be more reliably regulated, and the formation position of the upper thread loop can be made constant.

  As described above, according to the sewing machine according to the present invention, the movement of the sewing needle to the front and rear when the upper thread loop is captured by the sword tip of the inner hook is restricted, and the formation position of the upper thread loop is made constant. By doing so, the upper thread loop can be surely captured by the sword tip. As a result, the upper thread loop cannot be captured by the sword tip, skipping occurs, and the sword tip pierces the upper thread loop to reliably prevent the upper thread loop from being broken or raised. The sewing quality can be improved.

  Hereinafter, an embodiment of a sewing machine according to the present invention will be described with reference to FIGS. Here, in the present embodiment, the side operated by the operator in the sewing machine is the front side, the opposite side is the rear side, and the inner hook rotates in a reciprocating direction at a predetermined angle as a hook mechanism that crosses the upper thread with the lower thread. A sewing machine using a half-turn shuttle that moves (reciprocates and makes a half-turn) will be described.

  FIG. 1 is a schematic exploded perspective view showing a half-turn hook in the sewing machine of this embodiment, and FIG. 2 is a schematic perspective view showing the half-turn hook in FIG.

  As shown in FIGS. 1 and 2, the half-turn hook 2 of the sewing machine 1 according to the present embodiment includes an inner hook 3 that holds a bobbin case (not shown), and a driver 5 that rotates the inner hook 3 so as to be reciprocally movable. And a cauldron-shaped cauldron 6 that holds the inner cauldron 3 rotatably inside.

  The cauldron 6 is fixedly attached below a needle plate (not shown) in the bed portion of the sewing machine 1, and a hook shaft 7 that is driven in synchronization with a sewing machine main shaft (not shown) is inserted into the bottom wall 6 a of the cauldron 6. A through-hole 6b is formed. A hook shaft 7 is loosely fitted in the through-hole 6 b of the cauldron 6, and the leading end of the hook shaft 7 is positioned inside the cauldron 6. A substantially flat thread control plate 9 is fixed to the upper surface of the cauldron 6 by a fixing screw 10, and a through hole 9 a is formed at the needle drop position of the sewing needle 12 on the thread control plate 9. . The sewing needle 12 is positioned inside the inner hook 3 through the through hole 9a of the thread control plate 9 when lowered, and ascends after reaching the bottom dead center as shown in FIGS. At this time, an upper thread loop 13a is formed on the rear side of the sewing needle 12 outside the driver 5 and inside the cauldron 6 by the sewing thread 13 inserted into the needle hole 12a. At this time, the thread control plate 9 is configured to crawl the upper thread loop 13a that is pulled up to the outside of the cauldron 6 as the sewing needle 12 is raised by the through hole 9a.

  The inner hook 3 is accommodated inside the cauldron 6, and the inner hook 3 is rotatably held inside the cauldron 6 by an inner hook press (not shown). The inner hook 3 includes a fan-shaped bottom wall 3 a disposed to face the bottom wall 6 a of the cauldron 6, and a peripheral wall 3 b that is connected to the bottom wall 3 a and is disposed to face a part of the inner peripheral surface of the cauldron 6. A sharp sword tip 3c formed at one end of the peripheral wall 3b in the rotational direction for capturing the upper thread loop 13a, and a bobbin case formed at the center of the bottom wall 3a for rotating the inner hook 3 And a bobbin shaft 3d.

  A screwdriver 5 is fixed to the tip of the hook shaft 7, and the driver 5 has a cylindrical fixing portion 5 a fixed to the tip of the hook shaft 7 and a peripheral portion of the inner peripheral surface of the cauldron 6. And a driver main body 5d having a curved peripheral wall 5b and a connecting portion 5c connecting the peripheral wall 5b and the fixing portion 5a along the shape of the inner peripheral surface of about half of the direction, and the fixing portion 5a and the driver main body 5d. Are integrally formed. The driver 5 follows the rotation of the hook shaft 7 inside the cauldron 6 and rotates in a forward direction (about 200 ° in the present embodiment) when the sewing needle 12 is raised (see FIG. 2 in the direction of arrow A), and when the sewing needle 12 descends, it rotates in a predetermined angle return direction (in the direction of arrow B in FIG. 2) so that it can reciprocate. Both ends of the driver main body 5d in both rotational directions are in contact with a part of the peripheral wall 3b of the inner hook 3, and the driver 5 presses the inner hook 3 with both ends, thereby 6, the inner hook 3 is reciprocated and rotated.

  A needle rear side receiving portion 5e that supports the rear surface facing the sword tip 3c of the sewing needle 12 that is lowered and located inside the inner hook 3 is provided at the distal end portion of the peripheral wall 5b of the driver main body 5d. The needle rear side receiving portion 5e regulates the movement of the sewing needle 12 to the rear side. Furthermore, a needle front side receiving portion 5f that supports the entire surface opposite to the rear surface of the sewing needle 12 is formed at a distal end portion of the peripheral wall 5b of the driver body 5d with a predetermined gap from the needle rear side receiving portion 5e. The movement of the sewing needle 12 to the rear side is regulated by the front needle side receiving portion 5f. Thereby, the driver 5 presses the inner hook 3 by the tip of the needle rear side receiving portion 5e when rotating in the backward direction.

  A gap between the needle front side receiving portion 5f and the needle rear side receiving portion 5e in the driver 5 is a passage 5g of the sewing needle 12 when the lowered sewing needle 12 enters the inside of the inner hook 3. The needle front side receiving portion 5f and the needle rear side receiving portion 5e are respectively provided at the tip portions of the needle front side receiving portion 5f and the needle rear side receiving portion 5e when the driver 5 is disposed inside the cauldron 6 together with the inner hook 3. Is formed in a shape that is arranged at a position overlapping with the tip of the sword tip 3c of the inner hook 3 in the rotation direction.

  Further, as shown in FIG. 5, the needle front side receiving portion 5f and the needle rear side receiving portion 5e have a sharp shape and the sewing needle 12 that moves up and down moves between the needle front side receiving portion 5f and the needle rear side receiving portion 5e. In accordance with the diameter of the sewing needle 12 when the sewing needle 12 is positioned in the passage 5g formed in the above, the size of the gap is formed to be gradually narrowed as the sewing needle 12 is raised. That is, the front needle side receiving portion 5f and the rear needle side receiving portion 5e are narrow in the passage path 5g where the narrow portion of the sewing needle 12 passes in the vertically moving sewing needle 12, and the thick portion of the sewing needle 12 The dimension of the portion through which the needle passes is formed in a thick shape, and the surface facing the needle rear side receiving portion 5e in the needle front side receiving portion 5f is the surface facing the needle front side receiving portion 5f in the needle rear side receiving portion 5e. It is formed in the shape which inclines with respect to.

  Next, the operation of this embodiment will be described.

  In the sewing machine 1 according to the present embodiment, first, a sewing needle 12 into which a sewing thread 13 is inserted is placed below the needle plate through a cloth disposed on the upper surface of a needle plate (not shown) and a needle hole formed in the needle plate. It descends and is located inside the inner hook 3 through the through hole 9a of the thread control plate 9 and the passage 5g of the gap between the needle front side receiving portion 5f and the needle rear side receiving portion 5e in the driver 5. Subsequently, when the upper thread loop 13a is formed on the rear side of the sewing needle 12 when the sewing needle 12 moves up after reaching the bottom dead center, the sewing machine 1 rotates in one direction of the shuttle shaft 7. When driven, the driver 5 is rotated in the forward direction, and the inner hook 3 is pressed by the driver 5 and rotated in the direction of arrow A, whereby the upper thread loop 13a is captured by the sword tip 3c of the inner hook 3.

  Here, when the sewing needle 12 is located at the bottom dead center, the sewing needle 12 is located at the innermost part of the passage 5g formed in the gap between the needle front side receiving portion 5f and the needle rear side receiving portion 5e of the driver 5, and the passage route. The width dimension of 5 g is located at the widest portion, and the sewing needle 12 passes through the passage 5 g of the driver 5 that gradually becomes thinner as the driver 5 rotates in the direction of arrow A while the sewing needle 12 rises. To do. Then, the sewing needle 12 passes through the passage 5g of the driver 5 until the sword tip 3c exceeds the position where the needle thread loop 13a is captured, whereby the front surface of the sewing needle 12 is supported by the needle front side receiving portion 5f of the driver 5. In addition, the rear surface is supported by the needle rear side receiving portion 5e, and movement to the front and rear is restricted.

  Subsequently, after the sewing machine 1 captures the upper thread loop 13a with the sword tip 3c of the inner hook 3, and further rotates the inner hook 3 to a predetermined angle in the direction of arrow A, the upper thread is raised by raising the sewing needle 12. By pulling the loop 13a upward, the upper thread loop 13a can be passed through the bobbin case housed in the inner hook 3. As a result, the sewing machine 1 performs sewing by causing the lower thread supplied from the bobbin case to the needle drop position through the needle hole 12a of the needle plate to intersect with the upper thread loop 13a.

  Thereafter, while lowering the sewing needle 12, the driver 5 is rotated in the backward direction following the rotation of the hook shaft 7 in the other direction, and the inner hook 3 is pressed by the driver 5 to rotate in the direction of arrow B. By doing so, the sword tip 3c of the inner hook 3 is positioned upstream of the formation position of the upper thread loop 13a in the forward direction of the arrow A.

  As described above, according to the present embodiment, the front surface of the sewing needle 12 is placed on the front needle receiving portion 5f from when the sewing needle 12 is located at the bottom dead center until it exceeds the position where the sword tip 3c captures the upper thread loop 13a. Since the back surface is supported by the needle rear side receiving portion 5e, not only the sewing needle 12 but also the forward movement can be restricted, thereby forming the upper thread loop 13a. The position can be made constant.

  Therefore, by restricting the movement of the sewing needle 12 in the front-rear direction when the upper thread loop 13a is captured by the sword tip 3c of the inner hook 3, and by making the formation position of the upper thread loop 13a constant, it is ensured by the sword tip 3c. The upper thread loop 13a can be captured. As a result, the upper thread loop 13a cannot be captured by the sword tip 3c, and skipping occurs, or the sword tip 3c pierces the upper thread loop 13a, and the upper thread loop 13a breaks or flutters. Can be reliably prevented and the sewing quality can be improved.

  Further, the clearance between the front needle receiving portion 5f and the rear needle receiving portion 5e is set so that the sewing needle 12 is positioned in the passage 5g formed in the gap between the front needle receiving portion 5f and the rear needle receiving portion 5e. The front and rear surfaces of the sewing needle 12 are formed so that the front and rear surfaces of the sewing needle 12 are gradually narrowed in accordance with the diameter of the sewing needle 12 as the sewing needle 12 is raised. Therefore, it can support more reliably. Thereby, the movement of the sewing needle 12 in the front-rear direction can be more reliably regulated, and the formation position of the thread loop can be made constant.

  In addition, this invention is not limited to the said embodiment, A various change is possible as needed.

  For example, in the present embodiment, in the driver 5, the fixing portion 5a and the driver main body 5d are integrally formed, and the needle front side receiving portion 5f and the needle rear side receiving portion 5e formed in the driver main body 5d are also integrally formed. However, the present invention is not limited to this, and as an example, the needle front side receiving portion 5f and the needle rear side receiving portion 5e configured by other members may be attached to the driver main body 5d.

1 is a schematic exploded perspective view showing an embodiment of a sewing machine hook according to the present invention. 1 is a schematic perspective view showing the hook of FIG. The schematic perspective view which shows the case where the driver provided in the shuttle of FIG. 1 is visually recognized from the front side The schematic perspective view which shows the case where the driver provided in the shuttle of FIG. 1 is visually recognized from the rear side FIG. 3 and FIG. 4 are schematic top views showing a case where the driver is viewed from the upper side. Schematic perspective view showing an example of a conventional sewing machine hook 6 is a schematic cross-sectional view showing the sewing needle, the upper thread loop formed on the sewing needle, and the position of the sword tip of the inner hook that catches the upper thread loop in the sewing machine of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sewing machine 2 Half turn hook 3 Middle hook 3c Blade tip 5 Driver 5a Fixing part 5b Peripheral wall 5c Connection part 5d Driver body 5e Needle rear side receiving part 5f Needle front side receiving part 5g Passage path 6 Large hook 7 Hook shaft 9 Thread control plate 12 Sewing needle 13 Sewing thread 13a Upper thread loop

Claims (2)

A sewing needle that forms an upper thread loop with the sewing thread;
A hook with a sword that captures the upper thread loop by a rotating operation;
A driver for rotating the inner hook in a reciprocating manner by a rotating operation;
The driver includes a needle rear side receiving portion that supports one surface of the sewing needle that faces the sword tip, and a needle front side receiving portion that supports the other surface opposite to the one surface of the sewing needle. Sewing machine.   The needle front side receiving part and the needle rear side receiving part have a sharp gap between the two receiving parts, and the diameter of the sewing needle when the sewing needle moving up and down is positioned in the gap. 2. The sewing machine according to claim 1, wherein the sewing machine is formed in a shape gradually narrowing in accordance with the size of the sewing needle as it rises.

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